Permanent Incisor Morphology Flashcards
Arch Traits
Traits that distinguish between maxillary and mandibular teeth
Set Traits
Traits that distinguish between primary and permanent dentition
Class Traits
traits that distinguish between classes of teeth, incisors, canines,
premolars, molars
Type Traits
traits that distinguish between the types of teeth in the same class
Maxillary Central Incisor: General Characteristics
Development
- Calcification – begins around 3 months
- Eruption - 7- 8 years
- Root completion – 10 years
- Lobe development – 4 lobes
- Replaces E, F
B. Naming Maxillary Central Incisors
Universal - #8, #9 FDI – 11, 21
Palmer - 1 1
C. Arch position
1. Adjacent to midline, very prominent
2. Mesial contacts each other, distal contacts the lateral incisors
D. General form
1. Trapezoidal from facial or lingual, triangular from proximal
2. Widest tooth mesiodistally of any of the anterior teeth
3. Largest and most prominent incisor
Maxillary Central Incisor: Crown outline form
trapezoidal
1. Longer incisally, shorter cervically
2. Longer inciso-cervically, than it is wide mesiodistally
Maxillary Central Incisor: Height of contour
cervical 1/3rd, rest is flat
1. Height of contour, contact area important in re-contouring &
replacement of teeth for esthetics and health
Maxillary Central Incisor: Mesial outline form
- Almost straight
- Mesial Incisal angle is sharp
Maxillary Central Incisor: Distal outline form
- More convex or rounded
- Distal Incisal angle more rounded than the mesial incisal angle
Maxillary Central Incisor: Incisal outline
- Can have 3 rounded protuberances called mamelons
- Wear occurs on the lingual
Maxillary Central Incisor: Developmental depressions, grooves, lines
- Vertical faint lines extending from incisal edge fading out at the
cervical
Maxillary Central Incisor: Imbrication lines
- Faint, curved lines running mesial to distal in the cervical 1/3rd-
- Surface manifestations of Stripes of Retzius as enamel is laid down
Maxillary Central Incisor: Contact area
- Mesial Proximal Contact - incisal 1/3
- Distal Proximal Contact - junction of incisal 1/3 and middle 1/3
Maxillary Central Incisor: Lingual fossa
shallow concavity on the lingual surface
Maxillary Central Incisor: Four borders
a. Cingulum - convexity in the cervical 3rd, represents the lingual
developmental lobe
b. MMR - mesial marginal ridge - nearly straight
c. DMR - distal marginal ridge - convexity (curved)
d. Incisal edge
Maxillary Central Incisor: Lingual pit
Sometimes present between the fossa and cingulum
Maxillary Central Incisor: Mesial View/ Distal View
A. Shape – triangular
B. The long axis of the tooth (Facial-Lingual root bisector) passes through the
incisal edge - long axis
C. Height of Contour - facial and lingual - cervical 1/3
D. Incisal wear - on the lingual, slopes lingually
E. Distal contour is more convex (rounded) than the mesial contour
F. Cervical curvature is greater on the mesial than any other tooth in the mouth
Maxillary Central Incisor: Incisal View
A. Crown Outline Form – Shape - triangular
B. Incisal wears on the lingual
Maxillary Central Incisor: Root
A. Single, conical, relatively straight
B. Length - 2-3 mm greater than crown
C. Slight mesial inclination
D. 1 root canal, located in the center of the tooth
a. Shape mirrors the configuration of the tooth
E. Pulp Horns - 3 pulp horns - mesial, distal, central (smaller and more rounded)
F. Root is narrower lingually than facially
Maxillary Central Incisor: Clinical Considerations
Root harder to scale from the lingual
1. Narrow root from lingual
2. Indirect vision
B. Appearance
1. Spaces between teeth
2. Enamel formation - possible defects
3. Color can vary
4. Size can vary
Maxillary Lateral Incisor: General Characteristics
Development
1. Calcification - begins around 1 year
2. Eruption - 8-9 years
3. Root completion - 11 years
4. Lobe development - 4 lobes
5. Replaces D, G
B. Naming Maxillary Lateral Incisors
Universal - #7, #10 FDI – 12, 22
Palmer - 2 2
C. Arch position
1. Second from midline
2. Mesial contacts the central, distal contacts the canine
D. General form
1. Resembles central incisor but smaller - more delicate & slender, except root length
2. More rounded than central incisor, curvatures, convexities, concavities are more prominent
3. Variations are more frequent than any other permanent except 3rd
molars
a. Peg laterals
b. Can be congenitally missing
Maxillary Lateral Incisor: Facial View
Crown Outline Form - trapezoidal
1. Smaller and more round than central incisor
2. More variations
a. Peg laterals or missing
Maxillary Lateral Incisor: Mesial outline form
- More rounded (convex) mesial incisal angle than central
Maxillary Lateral Incisor: Distal outline form
- More rounded (convex) distal incisal angle than central
- Distal incisal angle more rounded than mesial incisal angle
Maxillary Lateral Incisor: Incisal outline
- Not as straight because of more rounded incisal corners
- Can have 2 or 3 mamelons
Maxillary Lateral Incisor: Developmental lines & Imbrication lines
Are present
Maxillary Lateral Incisor: Contact areas
- Mesial - junction of incisal and middle 1/3rds
- Distal - middle 1/3rd
Maxillary Lateral Incisor: Lingual Aspect
More prominent anatomy
1. MMR - mesial marginal ridge, DMR - distal marginal ridge - both more prominent
2. Cingulum more pronounced, centered
B. Lingual fossae are usually deeper, more concave
C. Linguogingival groove
1. Horizontal groove between the fossa and cingulum, more likely
contains a lingual pit
2. Area of incisors most likely to develop decay
D. Linguogingival fissure - fissure that runs gingivally from the groove slightly to the distal
Maxillary Lateral Incisor: Mesial/Distal View
A. Very similar to centrals except smaller
B. On the facial - the cervical bulge
C. On the lingual - cingulum
D. Largest convexities seen in the cervical 1/3rd
E. Incisal edge is located just facial to the long axis or on the line
Maxillary Lateral Incisor: Incisal View
A. Resembles central except mesial marginal ridge, distal marginal ridge and cingulum are more prominent
Mandibular Central Incisor: General Characteristics
A. Development
1. Calcification - begins around 3 months
2. Eruption - 6-7 years
3. Root completion - 9 years
4. Lobe development – 4 lobes
a. Usually have mamelons
5. Replaces O, P
B. Naming mandibular central incisors
Universal - #24, # 25 FDI – 31, 41
Palmer - 1 1
Maxillary Lateral Incisor: Root
A. Single may have a distal curve
B. Crown-to-root ratio - root is 11/2 times the crown
1. Root length is usually equal to that of central incisor root, can be
slightly longer
2. Lateral’s crown is smaller
C. 1 root canal, in the center
D. Can have 3 minimal pulp horns - 2 less sharp, more rounded - mesial and distal horns, minimal centra
Mandibular Central Incisor: Arch position
- Adjacent to mandibular midline
- Mesial contacts each other, distal contacts the lateral incisors
Mandibular Central Incisor: General form
- Smallest crown of any permanent tooth
- Symmetrical mesial and distal halves
- Trapezoidal outline form, but not as drastic of a trapezoid as other
incisors
Mandibular Central Incisor: Facial View
A. Trapezoidal outline form
B. Height of contour - cervical 1/3
Mandibular Central Incisor: Mesial incisal angle
- Very straight
- Mesial incisal angle is very sharp, more than maxillary incisors
Mandibular Central Incisor: Distal incisal angle
- Straight, similar to mesial
- Distal incisal angle is sharp but can be slightly larger than mesial
incisal angle - but both are acute 90-degree angles
Mandibular Central Incisor: Incisal edge form
- After mamelons are worn, edge is straight and perpendicular to long axis of tooth
Mandibular Central Incisor: Developmental depressions
- Very shallow
Mandibular Central Incisor: Cervical line form
- Has a distal tendency
Mandibular Central Incisor: Imbrication lines
- Usually not present
Mandibular Central Incisor: Contact area
- Mesial – incisal 1/3rd
- Distal - incisal 1/3rd
Mandibular Central Incisor: Lingual View
A. Very smooth, little detail, much less than maxillary incisors
B. Lingual fossa - slight, indistinct marginal ridges
C. No grooves, pits, or fissures
D. Cingulum - not as prominent as maxillary, slightly offset to the distal
E. Height of contour - cervical 1/3rd
Mandibular Central Incisor: Mesial / Distal Views
A. Shaped much like maxillary but smaller, wedge-shaped
B. Height of contour
- Facial - cervical 1/3rd
- Lingual - cervical 1/3rd
Mandibular Central Incisor: Incisal edge location
- Slightly lingual to root bisector
Mandibular Central Incisor: Cervical line
- Curvature is almost equal, if not - mesial is greater than distal slightly
Mandibular Central Incisor: Incisal View
A. More diamond shaped
B. Incisal wear is toward the facial
C. Cingulum is slightly offset toward the distal
D. Wider labiolingually than mesiodistally
Mandibular Central Incisor: Root
A. Straight, single, but can have proximal fluting
B. One root canal
C. Three pulp horns
D. Curves slightly distally at the apex
E. Wider faciolingually than mesiodistally
Mandibular Lateral Incisor: Facial View
A. Height of contour – cervical 1/3rd
B. Incisal edge form - slopes gingivally toward the distal
C. Distal incisal angle is more rounded than mesial incisal angle
D. Mesial proximal contact - incisal 1/3rd
E. Distal proximal contact - incisal 1/3rd but more cervically located than mesial
F. Developmental grooves - more prominent than central
G. Imbrication lines - may be present
Mandibular Lateral Incisor: General Characteristics
A. Development
1. Calcification - begins around 4 months
2. Eruption - 7-8 years
3. Root completion -10 years
4. Lobe development – 4 lobes
5. Replaces N, Q
B. Naming Mandibular lateral incisors
1. Universa l- # 23, # 26 FDI – 32, 42
2. Palmer - 2 , 2
C. Arch position
1. Second from the midline
2. Mesial contacts the central, distal contacts the canine
D. General form
1. Larger, wider, and longer than the mandibular central incisor
2. Distal lobe more developed than central incisor
Mandibular Lateral Incisor: Lingual View
A. More developed cingulum but still barely visible
B. More developed marginal ridges than on mandibular central incisor
C. Deeper lingual fossa than on mandibular central incisor
D. Cingulum offset toward distal
Mandibular Lateral Incisor: Mesial / Distal Aspect Views
A. Distal surface is more rounded
B. Distal surface is shorter inciso-gingivally than mesial surface
C. Incisal edge is lingual to root bisector
D. Cervical line curves less on the distal
Mandibular Lateral Incisor: Incisal View
A. Cingulum displaced toward the distal
B. Not straight mesiodistally as is the central
1. Incisal edge curves toward the lingual in the distal portion of the tooth
C. Looks twisted on its base
D. Crown is not bilaterally symmetrical as is the central
Mandibular Lateral Incisor: Root
A. Single
B. Root length is longer, wider, thicker, and straighter than central incisor
C. Root canal - larger than central
D. Pulp horns - 3 horns
E. Root depression - more pronounced on the distal
